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Flashcards in Bone pathology 2 Deck (92)
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Outline how fracture management can lead to osteopaenia

- Stress protection
- Implants reduce stress on bone
- No early mobility due to repair, leads to reduced mineral deposition on bone
- Weakened and at risk of pathological fracture


Compare the radiographic appearance of a traumatic fracture compared with a pathological fracture?

Pathological fracture usually has more bony changes around the fracture site, more lytic areas


Compare osteitis and osteomyelitis

Osteitis: centripetal i.e. moving towards marrow
Osteomyelitis: centrifugal i.e. starts in marrow and moves out


Describe the appearance of osteomyelitis on radiography

- Disorganised, areas of lucency
- Soft tissue swelling
- Irregular, semi-aggressive periosteal reaction
- More extensive than fracture callus
- Area of sclerosis around focus


What features are assessed in the determination of an aggressive vs non-aggressive lesion on radiography?

- Lysis
- Periosteal reaction pattern
- Lytic edge character
- Cortical disruption
- Transition zone
- Rate of change (10-14 days)


Briefly outline the bone lysis patterns that may be seen and rank these from non-aggressive to aggressive

- Geographic (single, well demarcated focus)
- Geographic (more aggressive if affecting only medulla)
- Moth eaten lysis (multiple areas)
- Permeative lysis (most aggressive)


Describe the benign (continuous) periosteal reaction patterns

- Lines parallel to the cortex typically
- Solid, lamellar (flat line), lamellated (slight rounding)


Briefly describe the interrupted (aggressive) periosteal reaction patterns and rank these from least to most aggressive

- Thick brush like (thick lines of periosteum perpendicular to the cortex)
- Think brush like (think lines)
- Sunburst (lines of periosteum from focus moving outwards in a divergent pattern)
- Amorphous bone production (no lines visible, disorganised)


What determines a radiographic lesion as aggressive, semi-aggressive or non-aggressive?

The most aggressive radiographic sign is used to determine the lesions degree of aggressiveness


What disease may be suggested by non-aggressive, slow developing radiographic signs?

Degenerative joint disease


Compare the radiographic appearance of neoplasia and infection in terms of degree of aggression

- Neoplasia: aggressive if malignant
- Non-aggressive/semi-aggressive if benign
- Infection: often semi- aggressive


Describe the orientation for viewing a lateral radiograph

- Proximal part of limb at top of image
- Cranial aspect of limb to the left


Describe the orientation for viewing a craniocaudal radiograph

Proximal part at the top


Describe the orientation for viewing a ventrodorsal radiograph

- Cranial part at the top
- Left marker on the right of the image when viewed


What normal feature of bone may commonly be mistaken as a small fracture?

Nutrient foramen


What are the advantages of MRI for imaging of the spinal column?

- Cross sectional image avoids superimposition
- Excellent soft tissue definition


Describe the appearance of discospondylitis on MRI

- Loss of signal from nucleus pulposus so appears hypointense
- Maybe some dislocation of vertebrae


Outline the advantages of CT in imaging of the spinal column

- Can be combined with myelography
- Can be useful where MRI not feasible e.g. metal implants
- Avoids superimposition
- Better for osseous structures vs. MRI


Describe the appearance of the subarachnoid space on a transverse CT myelogram

Radiopaque circle within the vertebral canal


Briefly outline the principles for myelography

- Injection of water-soluble non-ionic iodine contrast medium into the subarachnoid space
- Use of non-ionic medium in order to reduce side effects


What locations are used for the injection of contrast medium for myelography?

- Cisterna magna
- Caudal lumbar suubarachnoid space


What are the risks associated with myelography?

- Short term side effects e.g. incoordination
- Injection into spinal cord itself can result in permanent paralysis, or rarely, death


Compare cisternal and lumbar puncture for myelography

- Cisternal technically easier but less useful for thoracolumbar lesions as contrast may not reach that far
- Lumbar technically more difficult, better for thoracolumbar or lumbar lesions, may have less risk as not injecting near to proximal spinal cord


What modalities can be used for head and neck imaging?

- Radiography
- Ultrasound
- CT


Outline the limitations of radiography for imaging of the skull

- Anatomy complex
- Structures bilaterally symmetrical, can be impossible to distinguish on lateral views
- Accurate positioning difficult


What radiographic views can be taken of the skull?

- Lateral
- Dorsoventral
- Lateral oblique
- Rostrocaudal
- Rostrocaudal open-mouth
- Dorsoventral intraoral
- Ventrodorsal open-mouth oblique


Outline the positioning and centring for a lateral radiograph of the skull

- Lateral recumbency, nose and mandible raised with lucent pads to ensure sagittal plane of skull is parallel to the cassette
- Centre beam mid-way between eye and ear


Outline the positioning and centring for a dorsoventral radiograph of the skull

- Sternal recumbency, nose and mandible raised with lucent pads so transverse plane of skull is parallel to the cassette
- Centre beam mid way between medial canthi of eyes


What are the indications for use of a lateral oblique radiograph of the skull?

Imaging of the temporomandibular joints or bullae


Outline the positioning for a lateral oblique radiograph of the skull

- Wedge pad to raise rostral aspect of the head
- Lateral recumbency